Use of condoms has been expanding, in increased recognition of its effectiveness for contraception and in preventing infection to sexually transmitted diseases. However, various products in various shapes were developed in the trend toward reduction in thickness, and there are efforts aimed at developing products that give more natural and pleasant impression of use and thus satisfying the demand of the people who want traditional functions as well as an additional function to improve sex life.
In the efforts above, there are various inventions aimed at tightening the neck region of the penis, preventing drop out of condom, elongating sexual act, and preventing leakage of semen (e.g., Japanese Unexamined Utility Model Publication No. 1994-36621, Japanese Unexamined Patent Publication No. 2002-136533, and Japanese Registered Utility Model No. 3055221). However, when part of condom is made narrower, the diameter of the condom when it is rolled up becomes narrower, causing a problem that it was difficult to ensure the diameter of the condom to a length sufficient for easy placement; and because of that, there was no commercially available condom product that sufficiently tightens of the penis.
There is an invention similar to the present invention of holding and rolling the condom as the opening thereof is expanded in the tubular region of the condom (International Application WO 88/02624), but the condom demanded time for removal of the placement aid and also caused a concern about the damage of the condom by friction between the placement aid and the condom during placement, because the rolled condom is fixed on the placement aid.
In addition, there is an invention aimed at tightening the neck of the penis with a ring for prevention of fall out of condom (e.g., Japanese Patent No. 2607222), which also demanded a labor to place a condom as well as a ring or the like.
As apparent from the fact that there are so many inventions and devices, reduction in the diameter of the tubular region of the condom and easiness in placement of condom give an incompatible problem.